Car running wierd and throwing p1500 and p0505 code

[Shwillbo00]

i just bought this car a week ago...drove it back home 110 miles and right when i got infront of my house the check engine light came on. i got my own obd2 reader and scanned it..its throwing a p1500(alternater fr terminal malfunction) code and a p0505(idle control Sensor) code.. the p0505 im not worried about but the p1500 code on the other hand...im pretty good with engines and ive owned and worked on a few dsms...ive also been looking on here about the p1500 code and i realize it could either be my alternater, the wiring from the alt. to the brain or the brain itself. My car runs and rides fine but idles at like 900-1000 rpms and sumtimes jump to about 1400- 1500 rpms and then back down to 900...it doesnt act like it wants to die...just idles really wierd..last night i checked the 4 pin connecter on the alt. to make sure it was plugged in and im sure it was...i know luv2rallye has obviously ran into this problem before so hopefully he can better explain this problem to me...any help will be very highly appreciated!!!

 

[NJresident]

So I changed the tps and it didn't make a difference, car is idleing at 1500in park or neutral, and about 800 to 1000 in gear, when I turn on lights(hids) idle lowers, car still jerks when coming to a stop and now the gear lost is happening more often, irradict idleing, should I go ahead and change the isc? Still same and only code p0505, id apreciate some guidence

 

[buhay6]

I'll try and look some stuff up for you, I don't have much knowledge (still new to the DSM) but I'm always willing to learn more and help people find their answers.
If no one else replies to the thread maybe start a new one?